Local ventilation is a type of system in which the supply of air mixture to a certain point in the room is ensured - supply ventilation, or the removal of contaminated air mixture from the place of formation of harmful emissions - an exhaust-type system of action.
The supply-type system supplies pre-cleaned and heated air, the exhaust system removes the air mixture from a certain place in the room, where the highest concentration of harmful particles in the air is observed.
The simplest example of local ventilation is a conventional cooker hood, which removes air from the space above the stove. Most often, such ventilation systems are used in industrial premises, but also in residential premises it is not so rare.
Where local ventilation is required
A system that discharges used air to the outside should be installed in any home. In particular, its presence is required in those rooms, inside which various odors, smoke, gases, dust particles and other things accumulate. For example, for owners of private houses where there is a built-in garage, it is important to take care of the presence of a functional and efficient air duct system, along with which a device is installed that provides forced air extraction. If this is not taken care of, the exhaust gases will penetrate into the living part of the room and through the doors, and even through the walls of the room.
Local ventilation should be in the kitchen as well, since various odors always accumulate in any room of this type. Although many of them are quite pleasant, their constant presence is completely out of place. That is why local ventilation in such a part of the house is an important condition for the comfort of the kitchen.
Another room in the house that needs a high-quality ventilation system is a bathroom. Without an air outlet, the walls of this room, along with the ceiling, will soon be covered with mold.
You should also not forget about such a part of the house as a bathroom. Multiple air exchange is required there, especially if it is separated from the bathroom and has a very limited space.
What is local ventilation
Exhaust local ventilation is a type of device that quickly removes used air and any contaminants directly from the place of their origin. Such devices are indispensable when the part of the room where harmful particles appear is localized, it is necessary to prevent their spreading to the rest of the room.
Local ventilation of this type makes it possible to capture and promptly remove certain types of emissions - smoke, dust, gases, excess heat generated during the operation of certain equipment. The functioning of ventilation of this type ensures the achievement of a good effect, it protects the respiratory system of all those who are inside. At the same time, the volume of the air mixture discharged by the system is quite insignificant.
Types of local ventilation systems
Local ventilation, used today in premises for different purposes, is quite diverse. This is due to the tasks that are being put forward for the system, as well as some of the features of its functioning.
This type of ventilation system is divided into categories according to some criteria:
- exhaust and supply type - depending on the purpose;
- depending on the coverage area - local and general exchange type;
- the way to carry out the withdrawal of the air mixture - natural or mechanical;
- design features - channelless and channel.
Ventilation characteristics
The effectiveness of natural ventilation is determined by the wind speed outside as well as the temperature. As a result, such a system is not always able to provide an adequate level of air exchange.
Therefore, where there is a need to quickly remove a certain amount of air mixture, and supply the same amount of fresh air in its place, local ventilation with a mechanical type of work is often used. When using such a device, fresh air of a given humidity and temperature is brought to the right place, which fully meets the necessary standards and requirements.
Exhaust ventilation removes low-quality air even over long distances, before it enters the atmosphere, the mixture can be cleaned.
If necessary, supply and exhaust systems are automatically switched on and off at a specified time, which made their use in production very convenient.
Mechanical air purification systems for transmitting it over distances are equipped with some important components:
- fans and electric motors, which ensure the transfer of the mixture;
- heaters and dust catchers for the required processing of the mixture;
As a result of these properties, exhaust devices imply quite high energy costs. But such systems promptly remove and supply the air mixture to local zones in any conditions. If necessary, the air mixture lends itself to some types of additional processing - increasing humidity, cooling or heating, cleaning.
Local exhaust system
Local ventilation, which ensures the removal of the contaminated air mixture, is most effective when the place where any contamination is released is completely localized. In this case, it is usually required to prevent further spread of the contaminated air mixture throughout the rest of the space.
An exhaust air purification system of local action is more often used in production, where it effectively and efficiently removes all kinds of harmful particles from the air: smoke, gases, ordinary dust, as well as heat from operating devices. In order to remove such substances, local suction is used - a type of shelter, which can take the form of casings for this or that equipment, umbrellas, cabinets and the like.
The main requirements for such equipment are as follows:
- the place in which the discharge is formed, as covered as possible;
- the local suction has a well thought-out design, so that its use does not interfere with the functioning of the equipment;
- all contaminants from the place of their release should be removed in the same direction in which their natural movement occurs: high temperature vapors - up, dust - down;
- local ventilation must purify the mixture before venting the spent mixture into the atmosphere.
The most complex exhaust equipment is considered to be one that provides an increased degree of purification of exhaust air from dust and all other contaminants.
Local ventilation of this type is highly effective, since it removes harmful substances directly from the places of their release and formation, preventing them from spreading throughout the entire space of the room. Since most of the harmful substances that are released into the air mixture are distinguished by a significant concentration, a good hygienic effect is achieved with a relatively small volume of exhaust air.
However, it should be noted that such systems are far from always capable of efficiently solving their tasks.
This will be the case, for example, if the pollution is distributed over a large volume of space, if the supply of fresh air mixture to individual zones does not provide the required air parameters, if work involving the release of polluting substances in the air mixture is carried out simultaneously over a large area.
Varieties of local suction
One of the main varieties of this type of exhaust device is local suction. At the moment, there are several types of such equipment.
Semi-open suction - fume hoods are most often used as such equipment, sometimes ventilated chambers.
Such devices can provide the fastest and most efficient removal of small particles from the air at low air consumption. There are several types of such suction. To remove substances from the air at high humidity, as well as at high temperatures, equipment with an exhaust hood located in the upper part of the device is used. Cabinets equipped with a lower intake of the air mixture are used for the withdrawal of "heavy" air mixture. Portable devices, where the intake of the air mixture is carried out from the side, are mainly used to remove dusty types of contaminants.
Open devices - an exhaust structure located behind the source of contamination. At the moment, the most common devices in this category are side suction and exhaust hoods.
A side air intake device is used when it is required to have access to the source of emission of pollutants from all sides. Exhaust umbrellas are one of the simplest types of such equipment. They are installed in places where the emitted pollution is independently understood upward. Good efficiency of this type of equipment is achieved due to the significant volumes of the removed air mixture.
The closed air intake looks like a large cover, where there are special holes, through which air enters the equipment along with pollutants.
Considering all of the above, it can be confidently asserted that local exhaust ventilation is an excellent way to quickly and efficiently remove a contaminated air mixture from a localized place, preventing it from spreading to the rest of the room. In this case, the removed air is replaced with the same amount of fresh air.
Due to its characteristics, this type of air mixture purification systems is intended for use primarily in production, but sometimes such ventilation can be found in residential premises.
